1. Field of the Invention
This invention relates to a device displaying a body section, a method for displaying a body section and a medium for storing a program for realizing the device. More particularly, the present invention relates to a device displaying a body section, a method displaying the body section and a medium storing a program for realizing the device which makes the observation of the effective section of complex bodies.
2. Description of the Prior Art
According to the range of design methods using three-dimensional CAD, various techniques and devices for reviewing the design object by a computer in advance of a trial production of products are developed. Particularly the effective observation of bodies in a three-dimensional space by a computer is desired.
There are two ways for observing the bodies in the three-dimensional space by a computer. One is a technique for rapidly displaying the object, another is a technique for easily reaching an observed point.
In the technique for rapidly displaying an object, methods to reduce the loads, simplifying the object body, or neglecting some parts which are not seen in displaying are mainly used.
On the other hand, as a technique that displays a necessary section of the parts, control of sections that are not displayed are eliminated, or a transparency control technique is used making portions set before a viewpoint in three-dimensional space transparent. Other techniques only display a two-dimension display of a cut section. By using theses techniques, the relation of position between the arranged complex bodies or hidden parts can be observed, so that the object body can be effectively investigated.
Specifically the method for displaying the section of the object body is the most effective method to observe the object. And so, a technique for displaying effectively the section is desired.
In the prior art, when a section of an object body in a virtual three-dimensional space of a computer is generated, a plane parallel to the display screen is defined as a plane for generating the section to display a section parallel to the screen. In addition, the user decides a depth of the section to be displayed and the section of the two-dimensional plane is displayed.
As mentioned above, in the prior art, when a position of the plane for generating the section is defined in parallel to the display screen, the parts of the object body exists in the user side before the plane for generating the section is neglected in displaying them, and the two dimensional section of the object body is displayed.
In the prior art, the user transfers or rotates the object, and decides the plane for generating the section parallel to the display screen, and displays the two dimensional section which the user needs. Thus, functions that the two dimensional section is generated are based on the section which is determined in the three-dimensional space.
As mentioned above, in the prior art, as a plane for generating a section is defined in parallel to the display screen, when the object is transferred or rotated, the section displayed after the transfer or the rotation is different from the section before the transfer or the rotation.
That is, as the plane for generating the section is not defined, when the object body is transferred or rotated, the plane from the different angle is not shown, but rather a two-dimensional section at another point is shown.
While the prior art techniques generate a two-dimensional section cut at a plane at designated point by the three dimensional space, the generated section in the three-dimensional space is only displayed by a two-dimensional section parallel to the screen but cannot be displayed by the three-dimensional section.
Moreover, changing the position of the section set in the three-dimensional space, the user input the coordinates of each position, or a redefinition by using the two-dimensional chart are necessary. So, by the prior technique, users cannot seize the inner part of the body easily at a glance.